With the ever increasing demand for higher bandwidths, there is an immediate need to provide larger chunks of spectrum to each user to enable convergence of various services and simultaneous use of spectrum by multiple users. Traditionally, spectrum has been statically allocated to licensed operators. Users served by the licensed operators are provided small resource blocks in time and frequency. This scheme may not provide high data rates in the order of 100s of Mbps or Gbps to multiple users simultaneously.
One of the basic problems of systems today is to let a number of devices share a common resource, i.e., the allocated spectrum, in an efficient manner so as to simultaneously meet all desired performance objectives, such as fairness, low latency, high throughput, spectral efficiency, reasonable overhead, high mobility, fast scheduling and stability.